| Re: Not connected pads [message #824 is a reply to message #706] |
Thu, 19 August 2004 17:20  |
Clemens Adler
Messages: 42
Registered: March 2004
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continuous participant |
From: *kip.uni-heidelberg.de
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Hello,
an update on the issue of not connected pads:
We tested 8 padplane panels,
-4 of them are completely OK.
-2 have one unconnected pad.
-1 has 2 unconnected pads.
-1 has 6 unconnected pads.
in the case of 1 or 2 unconnected pads, I connected them to their outside neighbor, so they will not float.
In case of the 6 unconnected pads, I'm a bit unsure what to do. They are more or less in the middle of the chamber and they are in one block of 4 unconnected pads then 1 connected one, then 2 more unconnected pads. I.e. shorting them all, would mean a rather big block of dead channels right in the middle. The question is, whether we can still use that panel, or not.
Another issue is, that it is still not clear what the cause of the missing connection is: either bad soldering joints, that are not detected when the padplanes are tested, or broken cabel traces (what could happen during transport, uncareful handling, or when gluing the padplane to the panel).
Therefore it might be interessting to cut open a panel to see what caused the problem (on the other hand, both things could happen in principle, and one would need some statistics to really learn something?!?)...
so anyway, if anybody has suggestions, ideas...
cheers,
Clemens
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